Piano-bridge.



L. H. BREITEN'BAGH.

PIANO BRIDGE,

APPLICATION P; 1111111111111 1.

L. H. BREITENBAGH.

PIANO BRIDGE.

UNITED STAT E PATENT OFFICE.

LOUIS H. BREITENBACH, OF NEW YORKjN. Y., ASSIGNOR T0 WILLIAM F. KEOGH, OF NEW YORK, N. Y.

PIANO-BRIDGE.

Specification of Letters Patent.

Application filed March 28, 1911.

.To all whom 'it may concern i Be it known that I, LOUIS H. BRErrnN- BACH, citizen of the United States, residing at New York, in t-he county of New York and State of New York, have invented cerf tain new and useful Improvements in Piano-l Bridges, of which the following is a specifcation.

My invention relates to pianos and p articularly to the bridges thereof upon which the strings are supported.

The object of my invention is the provision of a bridge which will cause the strings to give forth a softer and more mellow tone, the construction eliminating the metallic tone common to strings supported on bridges of the ordinary character. Bridges as ordinarily constructed are formed of strips of wood glued together to form a practically solid bridge.

My invention consists in making these bridges hollow instead of solid, the hollow portion of the bridge either extending con tinuously from end to end, but being closed at the ends or certain successive lengths of the bridge being hollow. Preferably the hollow bridge is formed by making a concavity on the under face of the bridge next to the sounding board.

My invention is illustrated in the accompanying drawings wherein:

Figure l is a face view of a sounding board of a piano with my bridges applied thereto. Fig. 2 is a perspective view of one form of treble bridge. Fig. 3 is a perspective fragmentary view of a bass bridge. Fig. 4 is a perspective fragmentary view of another form of treble bridge. Fig. 5 is a like View to Fig. 4 but showing another modification of the treble bridge. Fig. 6 is a cross section of the bridge shown in Fig. 2. Figs. 7 and 8 show cross sectional views of my improved bridge illustrating the different forms which may be given to the groove 3.

Corresponding and like parts are referred to in the following description and indicated in all the views of the accompanying drawings by the same reference characters.

Referring particularly to Fig. 2, 2 designates one form of my improved bridge, which in this illustration is shown as a treble bridge. Only a portion of the treble bridge is illustrated. The treble bridge ordinarily is 4 feet long, 195 inches'rwide and 111; inches y deep. This bridge as ordinarily constructed is solid, and though it may be made up of several layers of wood, these layers are solidly glued to each other and form a bridge which rests flat down upon the sounding board.

As will be seen from Fig. 2, my improvement consists in forming the bridge with a concavity 3 in its lower face, this concavity in a bridge of the dimensions given being about l? inch deep and about l inch wide. As shown in Fig. 1, the bridge rests with its concave face against the sounding board 4 and the strings 5 of the piano pass across the outer face of the bridge and are held in proper spaced position by means of the usual pins 6. The recess or concavity 3 it will be observed when the bridge is in position con` stitutes a closed resonant chamber.

The closed resonant chamber or chambers formed as above described are peculiarly adapted to transmit sound vibrations to the sounding board, for the reason that inasmuch as the air is an elastic medium and can not escape from the resonant chambers, it will be set into vibration. by the vibration of the strings of the instrument, and this vibration will be communicated to the sounding board without any loss as would be the case were the chamber or chambers open at the sides. My invention, therefore, not only increases the delicacy of the instrument but increases the strength of its tone, at the same time eliminating the metallic tone which is incident to solid bridges and giving peculiar softness to the tone produced.

It will be understood that my invention does not consist in the general shape of the bridge but in the cross sectional shape thereof and the bridge may have any general shape desired or necessary to accomplish any particular purpose.

In Fig. 3 I show my improved form of bridge as applied to the bass strings of the instrument. In this form 7 designates the sounding board and 8 the bridge, having the concavity 9 on its under face. I do not wish to be limited to the exact shape of the groove or concavity 3, nor do I wish to be limited to a groove or concavity which extends along nearly the entire length of the bridge. This groove 3 may terminate short o f the ends of the bridge as illustrated in Fig. 2, or the bridge may be formed partly hollow,

that is, with a plurality of separated, relatively short grooves or conoavities l0, as illustrated in Fig. 4. The peculiar form of the groove 3 in the lower face of the bridgev may be varied as illustrated in Figs. rTand-8.

The particular advantage of a bridge of this charaoterris that the hollow resonant chamber or chambers formed by concavely recessing the under face of the bridge causes the strings to produce a softer and more mellow tone, and the `metallic tone which is incident to the ordinary solid bridges is entirely eliminated. It Will, of course, be understood that these bridges might be built up of strips ot' material glued to'each other, the bridge being afterward out out on its under side, or the bridge may be made of a solid piece. I do not wish to be limited either to the particular material used for the bridge, though Wood is preferable, orto thepartieular formof the bridge.

that I claimis:

l. The combination with a sounding board of a piano, of a bridge resting upon the sounding board and having a longitudinally extending series of recesses spaced and formingl a series of separated resonant chambers.

2. The combination with a sounding board of a. piano, of a bridge resting upon the sounding board and having a longitudinally extending concavity on the side toward the sounding board, the ends of the cavity being closed and the recess being less in Width than the Width of the bridge, and forming a closed resonant chamber.

In testimony whereof, I aHiX my signature in presence of two Witnesses.

`(Jopies of this patent maybe obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

